CULTURE OF THE CHOLERA SPIRILLUM. 323 



after being passed it is often difficult, because of the 

 large number of other bacteria that may be present, to 

 detect with certainty the cholera organism by micro- 

 scopical examination. It is advantageous in these cases 

 to mix the dejections with about double their volume 

 of slightly alkaline beef tea, and allow them to stand 

 for about twelve hours at a temperature of between 30° 

 and 40° C. There appears at the end of this time, 

 especially upon the surface of the fluid, a conspicuous 

 increase in the number of comma bacilli, and cover-slip 

 preparations made from the upper layers of the fluid 

 will reveal an almost pure culture of this organism. 



It is not improbable that a similar process occurs in the 

 intestines of those suffering from Asiatic cholera, viz.: 

 a rapid multiplication of the comma bacilli that have 

 gained access to the intestines takes place, but lasts for 

 only a short time, when the comma bacilli begin to dis- 

 appear, and after a few days their place is taken by 

 other organisms. 



In connection with his experiments upon the poison 

 produced by the cholera organism, Pfeiffer ' states that 

 in very young cultures, grown under the access of 

 oxygen, there is present a poisonous body that possesses 

 intense toxic properties. This primary cholera-poison 

 stands in very close relation to the material com- 

 posing the bodies of the bacteria themselves, and is 

 probably an integral constituent of them, for the 

 vitality of the cholera spirilla can be destroyed by 

 means of chloroform and thymol, and by drying, with- 

 out, apparently, any alteration of this poisonous body. 

 Absolute alcohol, concentrated solutions of neutral 



> Zeitscbrift f. Hygiene u. Infectionskrankheiten, Bd. zi, p. 393. 



